93f0d047cf
The conclusion is that this method really can tell the perfect from the less than perfect ACPI counters. It is in fact probably a bit more discriminative than that, but we will rather condemn some otherwise perfect counters to the slightly slower "-safe" version, than certify a counter as perfect which will let us down later. Many thanks to all the people who sent email reports!
368 lines
10 KiB
C
368 lines
10 KiB
C
/*-
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* Copyright (c) 2000, 2001 Michael Smith
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* Copyright (c) 2000 BSDi
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include "opt_acpi.h"
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#include <sys/param.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/timetc.h>
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#include <machine/bus_pio.h>
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#include <machine/bus.h>
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#include <machine/resource.h>
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#include <sys/rman.h>
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#include "acpi.h"
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#include <acpica/acpivar.h>
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#include <pci/pcivar.h>
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/*
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* A timecounter based on the free-running ACPI timer.
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*
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* Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
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*/
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/*
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* Hooks for the ACPI CA debugging infrastructure
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*/
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#define _COMPONENT ACPI_SYSTEM
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ACPI_MODULE_NAME("TIMER")
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static device_t acpi_timer_dev;
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struct resource *acpi_timer_reg;
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#define TIMER_READ bus_space_read_4(rman_get_bustag(acpi_timer_reg), \
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rman_get_bushandle(acpi_timer_reg), \
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0)
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static u_int acpi_timer_frequency = 14318182/4;
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static void acpi_timer_identify(driver_t *driver, device_t parent);
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static int acpi_timer_probe(device_t dev);
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static int acpi_timer_attach(device_t dev);
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static unsigned acpi_timer_get_timecount(struct timecounter *tc);
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static unsigned acpi_timer_get_timecount_safe(struct timecounter *tc);
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static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
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static void acpi_timer_test(void);
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/*
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* Driver hung off ACPI.
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*/
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static device_method_t acpi_timer_methods[] = {
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DEVMETHOD(device_identify, acpi_timer_identify),
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DEVMETHOD(device_probe, acpi_timer_probe),
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DEVMETHOD(device_attach, acpi_timer_attach),
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{0, 0}
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};
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static driver_t acpi_timer_driver = {
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"acpi_timer",
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acpi_timer_methods,
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0,
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};
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static devclass_t acpi_timer_devclass;
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DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
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/*
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* Timecounter.
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*/
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static struct timecounter acpi_timer_timecounter = {
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acpi_timer_get_timecount_safe,
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0,
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0xffffff,
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0,
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"ACPI"
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};
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SYSCTL_OPAQUE(_debug, OID_AUTO, acpi_timecounter, CTLFLAG_RD,
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&acpi_timer_timecounter, sizeof(acpi_timer_timecounter), "S,timecounter", "");
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static int test_counter(void);
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#define N 2000
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static int
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test_counter()
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{
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int min, max, n, delta;
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unsigned last, this;
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min = 10000000;
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max = 0;
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last = TIMER_READ;
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for (n = 0; n < N; n++) {
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this = TIMER_READ;
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delta = (this - last) & 0xffffff;
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if (delta > max)
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max = delta;
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else if (delta < min)
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min = delta;
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last = this;
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}
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if (max - min > 2)
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n = 0;
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else if (min < 0)
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n = 0;
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else
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n = 1;
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if (bootverbose)
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printf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
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n ? "GOOD" : "BAD ",
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min, max, max - min + 1);
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return (n);
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}
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/*
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* Locate the ACPI timer using the FADT, set up and allocate the I/O resources
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* we will be using.
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*/
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static void
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acpi_timer_identify(driver_t *driver, device_t parent)
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{
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device_t dev;
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char desc[40];
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int rid, i, j;
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ACPI_FUNCTION_TRACE(__func__);
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if (acpi_disabled("timer"))
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return_VOID;
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if (AcpiGbl_FADT == NULL)
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return_VOID;
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if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) {
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device_printf(parent, "could not add acpi_timer0\n");
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return_VOID;
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}
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acpi_timer_dev = dev;
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rid = 0;
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bus_set_resource(dev, SYS_RES_IOPORT, rid, AcpiGbl_FADT->V1_PmTmrBlk, sizeof(u_int32_t));
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if ((acpi_timer_reg = bus_alloc_resource(dev, SYS_RES_IOPORT, &rid, 0, ~0, 1, RF_ACTIVE)) == NULL) {
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device_printf(dev, "couldn't allocate I/O resource (port 0x%x)\n", AcpiGbl_FADT->V1_PmTmrBlk);
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return_VOID;
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}
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if (getenv("debug.acpi.timer_test") != NULL)
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acpi_timer_test();
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acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
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j = 0;
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for(i = 0; i < 10; i++)
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j += test_counter();
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if (j == 10) {
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acpi_timer_timecounter.tc_name = "ACPI-fast";
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acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
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} else {
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acpi_timer_timecounter.tc_name = "ACPI-safe";
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acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount_safe;
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}
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tc_init(&acpi_timer_timecounter);
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sprintf(desc, "%d-bit timer at 3.579545MHz", AcpiGbl_FADT->TmrValExt ? 32 : 24);
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device_set_desc_copy(dev, desc);
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return_VOID;
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}
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static int
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acpi_timer_probe(device_t dev)
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{
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if (dev == acpi_timer_dev)
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return(0);
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return(ENXIO);
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}
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static int
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acpi_timer_attach(device_t dev)
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{
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return(0);
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}
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/*
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* Fetch current time value from reliable hardware.
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*/
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static unsigned
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acpi_timer_get_timecount(struct timecounter *tc)
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{
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return(TIMER_READ);
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}
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/*
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* Fetch current time value from hardware that may not correctly
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* latch the counter.
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*/
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static unsigned
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acpi_timer_get_timecount_safe(struct timecounter *tc)
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{
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unsigned u1, u2, u3;
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u2 = TIMER_READ;
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u3 = TIMER_READ;
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do {
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u1 = u2;
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u2 = u3;
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u3 = TIMER_READ;
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} while (u1 > u2 || u2 > u3 || (u3 - u1) > 15);
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return (u2);
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}
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/*
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* Timecounter freqency adjustment interface.
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*/
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static int
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acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
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{
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int error;
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u_int freq;
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if (acpi_timer_timecounter.tc_frequency == 0)
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return (EOPNOTSUPP);
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freq = acpi_timer_frequency;
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error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
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if (error == 0 && req->newptr != NULL) {
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acpi_timer_frequency = freq;
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acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
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tc_update(&acpi_timer_timecounter);
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}
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return (error);
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}
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SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
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0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
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/*
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* Test harness for verifying ACPI timer behaviour.
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* Boot with debug.acpi.timer_test set to invoke this.
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*/
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static void
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acpi_timer_test(void)
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{
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u_int32_t u1, u2, u3;
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u1 = TIMER_READ;
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u2 = TIMER_READ;
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u3 = TIMER_READ;
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device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
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for (;;) {
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/*
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* The failure case is where u3 > u1, but u2 does not fall between the two,
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* ie. it contains garbage.
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*/
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if (u3 > u1) {
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if ((u2 < u1) || (u2 > u3))
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device_printf(acpi_timer_dev, "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
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u1, u2, u3);
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}
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u1 = u2;
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u2 = u3;
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u3 = TIMER_READ;
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}
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}
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/*
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* Chipset workaround driver hung off PCI.
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*
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* Some ACPI timers are known or believed to suffer from implementation
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* problems which can lead to erroneous values being read from the timer.
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*
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* Since we can't trust unknown chipsets, we default to a timer-read
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* routine which compensates for the most common problem (as detailed
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* in the excerpt from the Intel PIIX4 datasheet below).
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*
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* When we detect a known-functional chipset, we disable the workaround
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* to improve speed.
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*
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* ] 20. ACPI Timer Errata
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* ]
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* ] Problem: The power management timer may return improper result when
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* ] read. Although the timer value settles properly after incrementing,
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* ] while incrementing there is a 3nS window every 69.8nS where the
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* ] timer value is indeterminate (a 4.2% chance that the data will be
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* ] incorrect when read). As a result, the ACPI free running count up
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* ] timer specification is violated due to erroneous reads. Implication:
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* ] System hangs due to the "inaccuracy" of the timer when used by
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* ] software for time critical events and delays.
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* ]
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* ] Workaround: Read the register twice and compare.
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* ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
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* ] in the PIIX4M.
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*
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* The counter is in other words not latched to the PCI bus clock when
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* read. Notice the workaround isn't: We need to read until we have
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* three monotonic samples and then use the middle one, otherwise we are
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* not protected against the fact that the bits can be wrong in two
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* directions. If we only cared about monosity two reads would be enough.
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*/
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#if 0
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static int acpi_timer_pci_probe(device_t dev);
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static device_method_t acpi_timer_pci_methods[] = {
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DEVMETHOD(device_probe, acpi_timer_pci_probe),
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{0, 0}
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};
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static driver_t acpi_timer_pci_driver = {
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"acpi_timer_pci",
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acpi_timer_pci_methods,
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0,
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};
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devclass_t acpi_timer_pci_devclass;
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DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver, acpi_timer_pci_devclass, 0, 0);
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/*
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* Look at PCI devices going past; if we detect one we know contains
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* a functional ACPI timer device, enable the faster timecounter read
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* routine.
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*/
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static int
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acpi_timer_pci_probe(device_t dev)
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{
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int vendor, device, revid;
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vendor = pci_get_vendor(dev);
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device = pci_get_device(dev);
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revid = pci_get_revid(dev);
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if (((vendor == 0x8086) && (device == 0x7113) && (revid >= 0x03)) || /* PIIX4M */
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((vendor == 0x8086) && (device == 0x719b)) || /* i440MX */
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0) {
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acpi_timer_timecounter.tc_get_timecount = acpi_timer_get_timecount;
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acpi_timer_timecounter.tc_name = "ACPI-fast";
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if (bootverbose)
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device_printf(acpi_timer_dev, "functional ACPI timer detected, enabling fast timecount interface\n");
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}
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return(ENXIO); /* we never match anything */
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}
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#endif
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